According to James Consulting, Hitachi's newly developed MEMS accelerometers are more sensitive than current commercial MEMS accelerometers used in automobiles and smartphones, and consume 50% less power (Figure 1). The MEMS accelerometer has a noise density of 30 ng / √ Hz and is said to have the same noise level as the "large" accelerometers used in high-end areas such as aerospace, seismic and resource exploration (Figure 2). Figure 1 MEMS accelerometer and prototype development board Figure 2 Comparison of noise density between Hitachi's new MEMS accelerometer and traditional commercial MEMS accelerometer Hitachi's new MEMS accelerometers consume 20 mW, half the size of traditional MEMS accelerometers. If the MEMS accelerometer is applied to infrastructure (such as bridge and building) monitoring, gas pipeline and water pipe monitoring, and for oil and gas exploration, the cost of sensor usage can also be reduced. Reduce air resistance To increase sensitivity, Hitachi designed the structure of the new sensor. A typical MEMS accelerometer detects acceleration by the movement of a movable mass connected to a spring. Specifically, the acceleration is detected by a change in electrostatic capacitance between the moving electrode and the fixed electrode of the mass. However, when the mass moves in the air and the moving electrode hits the fixed electrode while moving, noise is generated, which affects the performance of the sensor. To this end, Hitachi reduces air resistance by making through holes in the mass (Fig. 3), and the diameter of the through holes varies between the upper and lower layers. The upper layer is the electrode portion and the lower layer is the moving layer with a larger weight. The above method can reduce the air resistance by about 50% or less. Figure 3 reduces the air resistance through the through hole (the diameter of the upper through hole is 30 μm, and the diameter of the lower through hole is 60 μm) brand vape pen, famous disposable vape brand, smok Shenzhen Xcool Vapor Technology Co.,Ltd , https://www.szxcoolvape.com
