AAS 198th Meeting, June 2001
Session 4. Instruments: Real and Proposed
Display, Monday, June 4, 2001, 9:20am-6:30pm, Exhibit Hall

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[4.03] Microshutter Arrays for the NGST MOS

B.E. Woodgate (NASA/GSFC), S. Aslam (Raytheon ITSS/NASA/GSFC), K.A. Blumenstock, A. Ewin (NASA/GSFC), R.K. Fettig, D. Franz (Raytheon ITSS/NASA/GSFC), C. Kotecki (NASA/GSFC), A.S. Kutyrev, M. Li, C. Monroy (Raytheon ITSS/NASA/GSFC), S.H. Moseley (NASA/GSFC), D.B. Mott, D.S. Schwinger, R.P. Wesenberg (NASA/GSFC), Y. Zheng (QSS)

Two-dimensional microshutter arrays have been developed at NASA Goddard Space Flight Center for the Next Generation Space Telescope (NGST) for use in the near-infrared region. Functioning as object selection devices, the microshutter arrays are designed for the transmission of light with high efficiency and high contrast. The NGST environment requires cryogenic operation at 45K. Arrays are close-packed silicon nitride membranes with a pixel size of 100\mum x 100 \mum. The mechanical shutter arrays are fabricated with Micro-ElectroMechanical Systems technologies. Individual shutters are patterned with a torsion flexure permitting shutters to open 90 degrees with a minimized mechanical stress concentration. The processing includes a Reactive Ion Etching (RIE) front-etch to form shutters out of the nitride membrane, an anisotropic back-etch for wafer thinning, and a deep RIE (DRIE) back-etch down to the nitride shutter membrane to form frames and to relieve shutters from the silicon substrate.

Two schemes for microshutter array actuation and selection are being developed. In the first approach shutters are addressed and selected by a CMOS circuit embedded in the shutter array frame. Actuation is performed by a macro-motion of the whole array support structure utilizing a double-shutter concept. In the second scheme the shutters are coated with a layer of high permeability magnetic material. They are rotated out of the plane by magnetic forcess produced by the interaction of the field produced by an external magnet that is swept across the shutter array and a metal layer on the shutters. To address the shutters a system of transparent electrodes, row and column address lines on each chip and external addressing electronics is used. Vertical walls of the shutter support structure are metallized and act as an electrode to hold selected shutters open at 90 degrees out of the plane.

This project is supported by NASA funding.

If you would like more information about this abstract, please follow the link to http://bram.gsfc.nasa.gov/ms_webpage/ms_animation.html. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

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