Study On Deposition Technology And Reliability Of Optical Film On Polycarbonate(PC) Surface

Polycarbonate(PC)is an optical plastic with excellent comprehensive properties.It is widely used in optical devices,information storage,automotive and aerospace fields.However,the current process of preparing optical films on PC substrates using the electron beam thermal evaporation method in industrial production is not yet complete,making the products produced with poor reliability and short life.Therefore,the optical film deposition technology needs further research and improvement to improve the reliability of the product.This article focuses on the reliability of current PC products.Through research and screening of material characteristics,Ti3O5 was selected as the high refractive index material and Si O2 was selected as the low refractive index material.Based on thin-film optical theory,Al-dielectric high-reflection film structures with Ti3O5 or Si O2 as protective layers were designed.Both designs have an average reflectance greater than 96% in the range of 400 ～ 700 nm.After testing and analyzing the thin films of the two film structures,a film structure with Si O2 as a protective layer was finally selected.In the preparation process,the surface of PC was modified by using low-energy ion beam treatment and transition layer technology to improve the surface energy of PC.The deposition process of Al was studied.By not using a crucible liner,the Al film material was directly deposited in the crucible point to evaporate,which solved the problems of large rate fluctuations and film splashing when the electron beam evaporated Al,and effectively improve the repeatability of the process.The samples were tested for reliability,and the thin film structure and preparation process were optimized based on the test results.An incremental ion source process is proposed,and the influence of the ion source process on the film properties is studied.The microstructure of the film was characterized by SEM.The results show that the incremental ion source process can effectively improve the film’s robustness.The method of adding Si O2 between the transition layer and the Al layer solves the problem of the Al layer peeling in the boiling test.Adopting annealing process and postplating ion beam treatment technology to improve film cracking problems in constant temperature and humidity test.By adjusting the outermost ion source process,the problems of the reflectance drop and spectral drift of the film after the boiling test have been improved.Finally,the samples passed multiple reliability tests.