J. Phys. IV France
Volume 112, October 2003
Page(s) 1185 - 1188

J. Phys. IV France
112 (2003) 1185
DOI: 10.1051/jp4:20031094

Optical scanner based on a NiMnGa thin film microactuator

M. Kohl1, S. Hoffmann1, Y. Liu1, M. Ohtsuka2 and T. Takagi3

1  Forschungszentrum Karlsruhe, IMT, Postfach 3640, 76021 Karlsruhe, Germany
2  Tohoku University, IMRAM, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
3  Tohoku University, IFS, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan

An optical scanner of 9 $\times$ 3 $\times$ 5 mm 3 size is presented, which is driven by a microactuator of Ni 2MnGa. The microactuator is fabricated by magnetron sputtering of a Ni 2MnGa thin film and subsequent photochemical micromachining. For operation of the scanner, a novel mechanism is proposed, which is based on the antagonism of magnetic and shape recovery forces. Thus, large bending forces in both actuation directions and low biasing forces can be generated simultaneously in a single microdevice. This mechanism is used to realize a large scanning angle of 50 deg. The dynamics of motion is characterized by heat-transfer times. Typical heating and cooling time constants are 2 and 16 ms, respectively. Below a critical frequency of about 55 Hz, the scanning angle is independent of the actuation frequency.

© EDP Sciences 2003