NDIR乙烷气体传感器中滤光膜的研制

Study and Fabrication of Filter in NDIR Ethane Gas Sensor

为满足NDIR乙烷气体传感器的使用要求,对气体探测系统中的滤光膜进行研制。根据甲烷与乙烷气体分子的红外吸收光谱,红外探测器的响应度以及系统的灵敏度确定了滤光膜的技术参数。选用Ge和Nb2O5分别作为高低折射率薄膜材料,根据拆分技术原理并借助膜系设计软件完成了滤光膜的双面设计,解决了滤光膜截止区域宽,且单面设计膜层应力过大的问题。采用直流脉冲磁控溅射真空镀膜的方法,制备的滤光膜在中心波长6.7μm处的透过率为72.09%,半峰值带宽为301nm,2.5~6.3μm和7.1~10μm的平均透过率为0.13%和0.01%,减小了其余干扰气体的影响,提高了探测系统的信噪比。薄膜样品经过了附着力测试,满足系统使用要求。

The optical filter in the gas detection system was studied and prepared to meet the requirements for NDIR ethane gas sensor.According to the infrared absorption spectrum of methane and ethane,the responsiveness of the IR detector and the sensitivity of the system,the technical parameter of the filter was obtained.Ge and Nb2O5 were chosen as the high and low refractive index materials respectively.Based on the principle of splitting technology,the double-sided filter design was completed by using membrane design software which solves the problem that the cut-off region was wide;and the stress of the single-sided filter design was too large.The filter which was prepared by DC pulsed magnetron sputtering system showed that the transmittance was 72.09%at 6.7μm,the FWHM was 301nm and the average transmittance of 2.5~6.3μm and 7.1~10μm was 0.13%and 0.01%,which reduced the impact of the remaining interference gases and improved the SNR of the detection system.The deposited coating was tested for adhesion to met the system requirements.