加速度計為量測振動加速度的儀器，基本的加速度計內含感測質量、彈簧、阻尼與感測器，並由其運動方程式可得知感測質量及感測器兩者的相對位移與外部加速度呈一比例關係，基於此概念，本研究開發一光學量測系統，以地震作為量測目標，系統需具有在XY平面上運動的功能且量測低頻或微小振動的特性，設計特殊結構之感測質量可感測微小振動及吸收劇烈振動並表現在感測質量的位移上，需要高靈敏度與精確的位移感測機制，因此利用雷射光及四象限偵測器紀錄並量測感測質量的位移變化。 根據實驗的結果，本研究之光學地震儀之量測加速度與頻率範圍為0.5 G與0.05~3 Hz，實驗量測最小加速度為5.9 mm/s2，系統之解析度為1.76 mm/s2。 ;Sensors that detect acceleration are called accelerometers. The basic elements of accelerometer are seismic mass, spring, damper and detector. We derived the motion equation of accelerometer knew the relative displacement between seismic mass and base, then there has a magnitude ratio between relative displacement and acceleration of base. Basic on the concept of accelerometer, we develop an optical seismic wave measurement system that is characterized by two-dimensional and low-frequency vibration detection. The design of seismic mass is low damping character to detect micro vibration and absorb massive vibration. Therefore, the optical measurement is characterized with the advantages of high sensitivity and precision to detect the displacement of the seismic mass. The experimental results show the measurement range of acceleration and frequency is 0.5 G and 0.05 to 3 Hz and the minimum experimental measuring acceleration is 5.9 mm/s2. The resolution of the system is 1.76 mm/s2.
