We focus on reliability-based tests of one-axis single crystalline silicon micromirrors and perfo... more We focus on reliability-based tests of one-axis single crystalline silicon micromirrors and performance in space environments. Reliability testing inhere shows how to deal with fabrication misalignment, charging effect, settling time reduction, shock and vibration in space, stiction in humidity, and reflectivity degradation related to outgassing. The micromirror in the international space station (ISS) actuated successfully under non-gravity condition as on earth.
Journal of Micromechanics and Microengineering, 2011
We report on the numerical analysis and demonstration of a two-degree-of-freedom (2-DOF) micromir... more We report on the numerical analysis and demonstration of a two-degree-of-freedom (2-DOF) micromirror with a large mirror plate and a reduced actuation voltage. The micromirror consists of two layers, namely, a top layer and a bottom layer. In the top layer, the flat reflection surface is comprised of single crystalline silicon, while the bottom layer has sloped electrodes allowing for a decrease in the actuation voltage. The sloped electrodes are fabricated by time-delayed electroplating using nickel. Two different types of electrodes, a cone-type electrode and a wedge-type electrode, are designed for the mirror plate actuation and for the frame actuation, respectively. The mirror size is 1.5 mm × 1.5 mm, and the distance between the top and bottom layers is 65 μm. The slope angle of the bottom electrode is 10.3 • for the cone-type electrode and 11.3 • for the wedge-type electrode. The mechanical maximum tilt angles are measured at 2.7 • with 127 V and 3.1 • with 120 V for the cone-type electrode and wedge-type electrode, respectively. The cone-type electrode and the wedge-type electrode provide decreased actuation voltages of 49.3% and 62.1%, respectively, compared to a parallel-type electrode. This design is useful for building large-size mirrors actuated by electrostatic forces.
We report on the design, fabrication and experiment of a 2-DOF silicon scanning micromirror. We p... more We report on the design, fabrication and experiment of a 2-DOF silicon scanning micromirror. We propose sloped electrodes to increase a maximum scan angle with a simple fabrication process. A delayed electroplating technique is adopted to fabricate the sloped profile of the electrodes over the patterned seed layer. We fabricated the 2-DOF scanning mirror which has different type of electrodes beneath each axis and compared with parallel plate electrodes. Experiment results show sloped electrodes increase stable range up to 62.1% and decreases actuation voltage down to 65.4% from parallel plate electrodes.
This paper describes MEMS micromirror characterization in space environments associated with our ... more This paper describes MEMS micromirror characterization in space environments associated with our space applications in earth observation from the International Space Station and earth's orbit satellite. The performance of the micromirror was tested for shock and vibration, stiction, outgassing from depressurization and heating, and electrostatic charging effects. We demonstrated that there is no degradation of the micromirror performance after the space environment tests. A test bed instrument equipped with the micromirrors was delivered and tested in the ISS. The results demonstrate that the proposed micromirrors are suitable for optical space systems. 2009 Optical Society of America OCIS codes: (230.3990) Micro-optical devices; (120.6085) Space instrumentation; (230.4040) Mirrors.
We focus on reliability-based tests of one-axis single crystalline silicon micromirrors and perfo... more We focus on reliability-based tests of one-axis single crystalline silicon micromirrors and performance in space environments. Reliability testing inhere shows how to deal with fabrication misalignment, charging effect, settling time reduction, shock and vibration in space, stiction in humidity, and reflectivity degradation related to outgassing. The micromirror in the international space station (ISS) actuated successfully under non-gravity condition as on earth.
Journal of Micromechanics and Microengineering, 2011
We report on the numerical analysis and demonstration of a two-degree-of-freedom (2-DOF) micromir... more We report on the numerical analysis and demonstration of a two-degree-of-freedom (2-DOF) micromirror with a large mirror plate and a reduced actuation voltage. The micromirror consists of two layers, namely, a top layer and a bottom layer. In the top layer, the flat reflection surface is comprised of single crystalline silicon, while the bottom layer has sloped electrodes allowing for a decrease in the actuation voltage. The sloped electrodes are fabricated by time-delayed electroplating using nickel. Two different types of electrodes, a cone-type electrode and a wedge-type electrode, are designed for the mirror plate actuation and for the frame actuation, respectively. The mirror size is 1.5 mm × 1.5 mm, and the distance between the top and bottom layers is 65 μm. The slope angle of the bottom electrode is 10.3 • for the cone-type electrode and 11.3 • for the wedge-type electrode. The mechanical maximum tilt angles are measured at 2.7 • with 127 V and 3.1 • with 120 V for the cone-type electrode and wedge-type electrode, respectively. The cone-type electrode and the wedge-type electrode provide decreased actuation voltages of 49.3% and 62.1%, respectively, compared to a parallel-type electrode. This design is useful for building large-size mirrors actuated by electrostatic forces.
We report on the design, fabrication and experiment of a 2-DOF silicon scanning micromirror. We p... more We report on the design, fabrication and experiment of a 2-DOF silicon scanning micromirror. We propose sloped electrodes to increase a maximum scan angle with a simple fabrication process. A delayed electroplating technique is adopted to fabricate the sloped profile of the electrodes over the patterned seed layer. We fabricated the 2-DOF scanning mirror which has different type of electrodes beneath each axis and compared with parallel plate electrodes. Experiment results show sloped electrodes increase stable range up to 62.1% and decreases actuation voltage down to 65.4% from parallel plate electrodes.
This paper describes MEMS micromirror characterization in space environments associated with our ... more This paper describes MEMS micromirror characterization in space environments associated with our space applications in earth observation from the International Space Station and earth's orbit satellite. The performance of the micromirror was tested for shock and vibration, stiction, outgassing from depressurization and heating, and electrostatic charging effects. We demonstrated that there is no degradation of the micromirror performance after the space environment tests. A test bed instrument equipped with the micromirrors was delivered and tested in the ISS. The results demonstrate that the proposed micromirrors are suitable for optical space systems. 2009 Optical Society of America OCIS codes: (230.3990) Micro-optical devices; (120.6085) Space instrumentation; (230.4040) Mirrors.
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Papers by Joo-Young Jin