SiAlON is chosen to replace SiO2, a commonly used low-refractive index material in the visible light band. Its refractive index at 550 nm is about 1.501, which is similar to that of SiO2. But its hardness can reach 1500 HV. In contrast, the hardness of SiO2 is 800 HV. Although the refractive index is similar, the hardness of SiAlON far exceeds that of SiO2. In the visible light waveband, the super-hard anti-reflection film made of SiAlON and Si3N4 has an average hardness of 1773.9 HV, and the average reflectivity is about 0.489% after the film system is optimized, which improves the film hardness while ensuring the anti-reflection effect. The film has passed a variety of environmental tests, which not only provides better protection for the display screens of electronic products, but also has important significance for other optical components that have higher requirements in terms of low reflection and high hardness.
Xiuhua Fu, Chengqi Tan, Gong Zhang, Xingyu Chen, Zhongju Ren, Yang Wang, Shuang Li. Research on Super-Hard Anti-Reflection Coatings for Screens[J]. Chinese Journal of Lasers, 2022, 49(6): 0603002
