Design and fabrication of two-axis micromachined steel scanners

This paper presents the fabrication and the test results of two-axis micromachined micro-mirror steel scanners developed for display and imaging applications. The novel fabrication method uses the conventional lithography and electrochemical metal etching techniques. A single photomask is used to define the whole structure, resulting in a simple and inexpensive fabrication process. Two different devices are designed, fabricated and characterized to test the proposed methods. Both of them employ the magnetostatic actuation to generate excitation force/torque. First device (Type-A) is a gimballed cantilever one, and it is capable of an optical scanning angle of 11.7◦ and 23.2◦ in slowand fast-scan directions, consuming a power of 42 mW and 30.6 mW, respectively. This structure has a quality factor of 287 in the slow-scan direction and a quality factor of 195 in the fast-scan one. The second device (Type-B) is a gimballed torsional one, and it has an optical scanning angle of 76◦ and 5.9◦ in slowand fast-scan directions, consuming 37 mW and 39 mW, respectively. This structure has a quality factor of 132 in the slow-scan and 530 in the fast-scan directions, respectively. The maximum total optical scanning angles obtained for the slowand fast-scan axes are 105◦ (gimballed torsional device, Type-B) and 42◦ (gimballed cantilever device, Type-A). (Some figures in this article are in colour only in the electronic version)