鎳基微慣性開關之開發

Abstract

本論文重點在於以電鍍鎳製程開發鎳基微加速度開關，針對及時偵測與被動感測不同的需求，分別設計了非卡榫式開關以及卡榫式開關元件。 非卡榫式微開關部分，乃針對及時偵測之需求，設計規格配合軍事用途。採用雙質量塊搭配質量塊連接樑，使懸臂樑受慣性力時，一端可作為懸臂彈簧控制加速度閾值，一端則作為撓性臂以達成降低反應時間與延長接觸時間之需求。開關經黃光電鍍製程後，加速度閾值於320G時未啟動，而在483.8G時啟動，反應時間為100μs，訊號維持時間為40μs，符合原設計需求。 卡榫式微開關部分，乃針對被動感測之需求，設計規格適用於物流業貨品運輸時碰撞偵測。本研究主要針對卡榫開關強健性及可回復之設計進行探討，卡榫開關強健性探討將利用與感測方向相反之加速度，驗證開關是否可穩定維持於導通狀態；可回復之設計採用外部磁鐵產生磁場，使開關結構受外部磁場產生磁扭矩，造成結構懸臂樑變形，使開關由導通狀態回復原始狀態。分別製作基底空間為2.2μm、41.5μm、59.4μm之開關，在卡榫開關強健性探討部分，經反向加速度-64.39G、-58.69G、-60.26G測試後，開關穩定維持於導通狀態，驗證此開關之強健性。在可回復部分，基底空間2.2μm之開關無法成功回復開關原始狀態；基底空間41.58μm之開關於磁場夾角由0˚轉至20˚時，回復原始狀態，但加速度閾值由35.73G變成44.3G；基底空間59.4μm之開關於磁場夾角由0˚轉至18˚時，成功回復原始狀態，但加速度閾值由31.65G變成38.69G，且無法穩定維持在close狀態。模擬結果顯示，以磁力回復力量會造成塑性變形，仍須修正實驗設計參數。

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 2.2μm, 41.5μm, 59.4μm. 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.