采用无电极谐振音叉的石英真空传感器设计

摘要

提出了一种基于气体输运现象的双参数谐振石英真空传感器(QRVS).与传统QRVS不同,在(zyw)-18°15′切型的石英音叉片本体无任何电极设置,构成“无电极型谐振音叉”;采用频率和等效串联电阻值的双参数谐振敏感机制,且音叉厚度t与两叉臂间距g之比为t/g =10.为了增大叉臂与真空中残存气体的机械摩擦阻尼,在叉臂的前端制备了4枚通透沟槽.为了抑制寄生振动模式,提高品质因数Q值和叉臂根部的机械疲劳寿命,在两叉臂的边缘分别制作了半圆形台阶,在支撑隔离区加工了2～5枚矩形槽.典型样品实测数据表明:真空测量范围为10-3～ 105 Pa,分辨率为3×10-3 Pa,准确度为10％F.S,稳定性为1.5 ×10-3Pa,达到了设计要求.%A design of quartz resonant vacuum sensor (QRVS) with two-resonant parameters based on gas transportation phenomenon is proposed.Its main differences with the traditional QRVS are stated as the follows:(zyw)-18°15′cut type quartz crystal tuning folk sheet is used in the QRVS,and the QRVS is not set any type of electrodes on its quartz tuning fork sheet which " a piezo-resonant tuning fork with no electrodes " is called.Resonance sensitive mechanism with two-parameter that are resonance frequency and equivalent series resistance are used,and ratio of thickness of tuning to distance between the two tuning arms,t/g is 10.In order to increase mechanical friction damping of residual gas in vacuum with fork arms,and four ventilated grooves on the upper end of the arm are prepared.In order to suppress spurious vibration modes,improve the quality factor Q value,and mechanical fatigue life of the fork arm root,the semicircular steps at the edge of two fork arms and 2 ～5 rectangular grooves in isolating support region are made,respectively.The measured data of typical samples of QRVS show that range of vacuum measurement is 10-3 ～ 105 Pa,resolution of vacuum measurement is 3 × 10-3 Pa,accuracy of vacuum measurement is 10 ％ F.S,stability is 1.5 × 10-3Pa,fully meet the design requirements.