MEMS scanning laser projection based on high-Q vacuum packaged 2D-resonators

U. Hofmann; C. Eisermann; H.-J. Quenzer; J. Janes; C. Schroeder; O. Schwarzelbach; B. Jensen; L. Ratzmann; T. Giese; F. Senger; J. Hagge; M. Weiss; B. Wagner; W. Benecke

doi:10.1117/12.878676

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14 February 2011 MEMS scanning laser projection based on high-Q vacuum packaged 2D-resonators

U. Hofmann, C. Eisermann, H.-J. Quenzer, J. Janes, C. Schroeder, O. Schwarzelbach, B. Jensen, L. Ratzmann, T. Giese, F. Senger, J. Hagge, M. Weiss, B. Wagner, W. Benecke

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Proceedings Volume 7930, MOEMS and Miniaturized Systems X; 79300R (2011) https://doi.org/10.1117/12.878676
Event: SPIE MOEMS-MEMS, 2011, San Francisco, California, United States

Abstract

Small size, low power consumption and the capability to produce sharp images without need of an objective make MEMS scanning laser based pico-projectors an attractive solution for embedded cell-phone projection displays. To fulfil the high image resolution demands the MEMS scanning mirror has to show large scan angles, a large mirror aperture size and a high scan frequency. An additional important requirement in pico-projector applications is to minimize power consumption of the MEMS scanner to enable a long video projection time. Typically high losses in power are caused by gas damping. For that reason Fraunhofer ISIT has established a fabrication process for 2D-MEMS mirrors that includes vacuum encapsulation on 8-inch wafers. Quality factors as high as 145,000 require dedicated closed loop phase control electronics to enable stable image projection even at rapidly changing laser intensities. A capacitive feedback signal is the basis for controlling the 2D MEMS oscillation and for synchronising the laser sources. This paper reports on fabrication of two-axis wafer level vacuum packaged scanning micromirrors and its use in a compact laser projection display. The paper presents different approaches of overcoming the well-known reflex problem of packaged MEMS scanning mirrors.

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U. Hofmann, C. Eisermann, H.-J. Quenzer, J. Janes, C. Schroeder, O. Schwarzelbach, B. Jensen, L. Ratzmann, T. Giese, F. Senger, J. Hagge, M. Weiss, B. Wagner, and W. Benecke "MEMS scanning laser projection based on high-Q vacuum packaged 2D-resonators", Proc. SPIE 7930, MOEMS and Miniaturized Systems X, 79300R (14 February 2011); https://doi.org/10.1117/12.878676

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