随着图像识别技术的不断发展,人脸识别系统对虹膜识别滤光片的要求不断提高,光在大角度入射时,光谱偏移量往往较大而导致识别失败,因此急需一种低角度效应良好的带通滤光片。利用光谱拆分原理设计了一种大角度、小偏移量的带通滤光片。通过调节氢气流量使得Si-H在增大折射率的同时仍能保持较低的吸收率,从而改善虹膜识别滤光片的角度效应。基于对薄膜材料沉积工艺的研究,采用一种特殊的膜系结构,解决了因薄膜内部结构疏松而发生的脱膜问题。测试结果表明,该膜系结构能满足虹膜识别滤光片的各项技术要求。

With the development of image recognition technology, the demand for face recognition systems with an iris recognition filter is constantly increasing. With large incident angles, recognition failure often occurs owing to a large spectral offset; therefore, a bandpass filter with good low-angle effect is required. Herein, a bandpass filter with large angle and small spectral offset is designed based on the spectral splitting principle. By adjusting the hydrogen gas flow, the refraction index of Si-H is improved while maintaining the low absorption, enhancing the angle effect of the iris recognition filter. Based on available literature on the deposition of thin films, the problem of film removal due to its loose internal structure is solved herein by adopting a special film system structure; testing results show that this structure meets the technical requirements of iris recognition filters.