Fabrication Of Wide-Angle Antireflection Films By PECVD Technique

As an important part of optical thin films, the anti-reflection films are being widely used in optical systems and optical devices. In some special environments, higher requirements are proposed for anti-reflection films, it is not enough to realize anti-reflection performance of a certain waveband. For example, the aircraft cabin usually needs to reduce unnecessary surface reflections of instrument, which have negative impact on human eyes. So the wideband anti-reflection films that have fine anti-reflection effect at a certain incident angle are required.The anti-reflection films at the incident angle from 0 to 50° and the waveband ranging from 400nm to 700nm (WAAF, short for Wide-Angle Antireflection Films) were designed and optimized in this paper. The WAAF was prepared by PECVD technology, and the manufacturing error was explored. Besides, the anti-reflection films at the incident angle from 51° to 80° and the waveband ranging from 400nm to 700nm were explored and designed. The main conclusions are as follows:1) Five WAAF were designed by using Needle, Fourier transform method, Inhomogeneous Refinement. The average reflectivity of five film structures at the incident angle of 50°nd the waveband ranging from 400nm to 700nm are 1.07%,0.96%,1.00%,0.88%,0.76%, respectively.2) The WAAF was prepared by PECVD technology. Average reflectivity of the WAAF at the incident angle of 50°and the waveband ranging from 400nm to 700nm is 1.3%. The layer thickness error was the main reason that causes the differences between theoretical spectral curve and measured spectral curve.3) The design feasibility of anti-reflection films at the incident angle from 0 to 80° and the waveband ranging from 400nm to 700nm was explored by combining with the method of Needle, Random Optimization and Inhomogeneous Refinement, which the average reflectance is less than 5%. The decisive factor that affects the optical properties of wide-incident-angle anti-reflection films is low refractive index material based on exploration. Only when low refractive index material is available and its value is 1.05, the anti-reflection films at the incident angle from 0 to 80° and the waveband ranging from 400nm to 700nm that the average reflectance is less than 5% could be designed.