940 nm滤光片的设计、制备及低角度效应的研究

Design and Fabrication of 940 nm Filter and Research on Its Low Angle Effect

本文对人脸识别中使用的940 nm窄带滤光片进行设计及制备,研制一种具有低角度效应的窄带滤光片。选择TiO_(2)、SiO_(2)作为高、低折射率材料,在Essential Macleod软件中对膜系进行设计,通过改变间隔层材料对膜系进行优化,最终设计的膜系层数为11,膜系总厚度为2480.76 nm。采用电子束热蒸发沉积技术对薄膜进行镀制,使用傅里叶红外光谱仪完成透射率光谱特性测试。最终研制的滤光片中心波长为940 nm,在截止区间(200~1100 nm)内,通带透射率大于80%,平均截止透射率小于1%,0°~22°通带偏移量为14 nm。

In this study,a 940-nm narrowband filter used for face recognition is designed and examined and a narrowband filter with low angle effect is developed.TiO_(2) and SiO_(2) are chosen as high and low refractive index materials,respectively.The film system is designed by using the Essential Macleod software and optimized by changing the material of the spacer layer.The film system has 11 layers and a total thickness of 2480.76 nm.The thin film is plated by using the electron beam thermal evaporation deposition technology,and the transmittance spectral characteristics are tested using a Fourier infrared spectrometer.The center wavelength of the finally developed filter is 940 nm.In the cut-off range(200 to 1100 nm),the pass-band transmittance is greater than 80%,average cut-off transmittance is less than 1%,and offset at 0°to 22°passband is 14 nm.