Electrostatically Actuated Two-Dimensional Optical Scanner Having a High Resonant Frequency Ratio of Fast/Slow Axes

Hiroshi NOGE  Yosuke HAGIHARA  Kiyohiko KAWANO  Hideki UEDA  Takaaki YOSHIHARA  

IEICE TRANSACTIONS on Electronics   Vol.E91-C   No.10   pp.1611-1615
Publication Date: 2008/10/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e91-c.10.1611
Print ISSN: 0916-8516
Type of Manuscript: INVITED PAPER (Special Section on Electronic Displays)
MEMS,  vertical comb drive,  optical scanner,  micro mirror,  laser display,  

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Two-dimensional resonant optical scanners actuated by vertical electrostatic combs with a unique electrical isolation structure have been developed. The isolation on the movable frame surrounding 1 mm-diameter gimbal mirror is made by trenching the top silicon layer of an SOI wafer with leaving the thick bottom layers. Thanks to the large mass of the frame, the resonant frequencies range in 65.0-89.2 Hz for the frame and in 11.9-36.8 kHz for the mirror in a 4 mm4 mm chip. The resultant frequency ratio of the fast/slow axes reaches over 500 and such a high frequency ratio is utilized to display QVGA image by raster scanning of a laser beam.