Microtechnology: Miniature Magnetic Switches

IME researchers have developed a novel passive magnetostatic microelectromechanical (MEMS) switch that is fabricated by micromachining technology. The switch is composed of an electroplated Ni80Fe20 plate that is supported by a pair of torsion bars. The patterning of the Ni80Fe20 plate into long and narrow strips confers sensitivity to the device, while the novel device structure and micromachining technology enable smaller device footprint (4 mm2 vs >12 mm2 ), better shock resistance (>500 g vs 50 g), and lower fabrication cost - compared to conventional reed switches. The switch also exhibits high sensitivity, low contact resistance and good reliability. The proposed switch has the potential to replace conventional reed switches in portable electronics, such as laptops, cellular phones and hearing aids.