液体产品的密度检测是审核产品品质的重要手段之一。针对当前传统密度检测装置体积大、功耗高、不易在线检测的问题, 该文设计并制作了一种基于压电微机械超声换能器(PMUT)的液体密度测量传感器。该传感器由两个PMUT(半径为500 μm, 空气中谐振频率为136 kHz)组成, 分别作为发射端与接收端。实验测试结果表明, 该传感器的谐振频率与液体密度成线性关系, 在776~1 150 kg/m3密度范围内具有良好的响应, 其灵敏度为17 Hz/kg/m3。

The density detection of liquid products is one of the important means to audit product quality. Aiming at the problems of large volume, high power consumption and difficulty of online detection of the current traditional density detection device, a liquid density measurement sensor based on piezoelectric micromachined ultrasonic transducer (PMUT) was designed and fabricated in this paper. The sensor consists of two PMUTs (the radius is 500 μm, and the resonant frequency in air is 136 kHz), which are used as the transmitting end and the receiving end, respectively. The experimental test results show that the resonant frequency of the sensor has a linear relationship with the liquid density, it has a good response in the density range of 776 to 1 150 kg/m3, and the sensitivity is 17 Hz/kg/m3.