2011RPM

馬瑞彬 (Ruei-Pin Ma)

Development of Nickel Micro Inertial Switches

鎳基微慣性開關之開發

This paper focuses on the development of nickel micro inertial switches. Two different kinds of switches, non-latching and latching are designed for the different needs of real time sensing and passive sensing.

The non-latching switch, which is demanded for real time sensing, is designed for the weapon application. The cantilever beam is separated as two parts by dual-mass with mass connection beam. One part is used as the spring; other part is used as a flexible beam for faster response and long duration contact. Switch is fabricated by the nickel-based electroplating. The switch is off after applying 320G impact, and it turns on after applying 483.8G impact. The reaction time of switch turning on is 100 μs; the signal duration time is 40μs. This result fulfills the design specification.

The latching switch, which is demanded for passive sensing, is designed for impact detection of transportation. The robustness of latching switch and the capability of resetting the switch is discussed. The reverse acceleration is used to verify the robustness of latching switch. For the capability of resetting the latch, the external magnets are used to induce magnetic field. The switch undergoes the magnetic torque by the magnetic field, resulting in deformation of the cantilever, so that switch reset. The switch is fabricated with suspended gap of 2.2 μm, 41.5 μm, 59.4 μm. After the reverse acceleration test, the switch remained stable. This result verifies the switch is robust. For the capability of resetting the latch, the switch of gap 2.2μm can’t be reset successfully. When the angle of the magnetic field and switch is changed from 0˚ to 20˚, the switches of gap larger than 41.58μm is reset, but the acceleration threshold has 24% difference, and these switches are not robust at all. According to the ANSYS simulation, the magnetic torque we used causes the switches plastic deformation. Some of switch parameter should be redesigned.

[1] C.-H. Chung, R.-P. Ma, Y.-C. Shieh, and W. Hsu (June 2011). A Robust Micro Mechanical-latch Shock Switch with Low Contact Resistance, The 16th International Conference on Solid-State Sensors, Actuators and Microsystems, Beijing, China.

[2] Y.-C. Shieh, R.-P. Ma, W. Hsu, Y.-H. Lin, and Y.-H. Tang (October 2012). A Reversible Micro Mechanical-latch Shock Switch by External Magnetic Field. The 11th IEEE Conference on Sensors, Taipei, Taiwan.