Preparation And Characterization Of Wide-band Non-absorbance And Anti-reflection Film Based On Optical Plastic Substrate

Nowadays,with the rapid popularization of all-electric injection molding machines,optical plastics are widely used in various fields due to their advantages such as low price,easy to obtain complex shapes and low quality.However,there still have some weakness which can significantly limit further the application and development of optical plastics such as large thermal expansion coefficient,serious hygroscopicity and easy to age under ultraviolet light.Therefore,it is very meaningful to investigate the characteristics of the anti-reflection film of the optical plastic substrate and improve the resistance of the optical plastic lens toward to different environmentsIn this project,a systematic theoretical and experimental investigations on the absorption characteristics of titania pentoxide film,the film layer's stress characteristics,and the aging characteristics of the multi-layer antireflection film on the optical plastic substrate were conducted.The main work and results are drawn as follows.(1)Ti3O5 thin films were fabricated on silicon substrates by electron beam evaporation method with different deposition parameters.The influence of oxygen partial pressure,baking temperature,deposition rate and ion source parameters on the refractive index and extinction coefficient of Ti3O5 films were studied by ellipsometer measurement method of optical constants.It was found that the Ti3O5 film with high refractive,low extinction coefficient can be obtained by reducing the oxygen partial pressure,improving the deposition temperature and rate.The Ti3O5 film with the smallest extinction coefficient(420nm/1.1×10-4)was selected,and its refractive index and extinction coefficient were taken as the material parameters of high refractive index.Besides,a wideband non-absorbance antireflective film with an average reflectance of 0.5%in 420-880nm band on optical plastic substrates was designed and optimized by TFCALA.(2)The thermal stress models of silicon substrate and optical plastic substrate multi-layer antireflection film were established in ANSYS,respectively.The thermal stress of multi-layer antireflective film on silicon substrate and optical plastic substrate obtained in simulation is 1.1GPa and-12.7GPa,respectively.The monolayer silicon dioxide film,monolayer titanium pentoxide film and multi-layer antireflection film were fabricated on the silicon substrate using the electron beam evaporation method with different deposition parameters.The residual stress of the film was characterized by profilometer,and the influence of baking temperature,oxygen partial pressure and ion source parameters on the residual stress of the films were investigated.It was found that under different deposition processes,the residual stress of monolayer film change from tensile stress to compressive stress,and the residual stress of multi-layer antireflection film on silicon substrate can be controlled between-23.7MPa and 1MPa through adjusting the deposition parameters.(3)The multi-layer antireflective films were fabricated on optical plastic substrate by electron beam evaporation method with different deposition parameters.The transmittance curves of films were measured by the spectrophotometer,and a multi-layer antireflective film with aborb of 0.1%at 420-880nm on optical plastic substrate was obtained.The aging characteristics of the anti-reflection film on optical plastic substrate was measured in different environments by using various aging test equipment.The test results demonstrate that high temperature and humidity can reduce the transmittance of the films,and by reducing the oxygen partial pressure,increasing the deposition temperature,and adjusting ion source parameters,an anti-reflection film with high temperature resistance and high humidity resistance can be obtained on the optical plastic substrate.Besides,it was found that the films suffer a strong aging reaction under the combined action of temperature,humidity,and ultraviolet rays,which can cause the films to crack.This film cracking effect can be effectively avoided and prevented by reducing the oxygen partial pressure,increasing the deposition temperature,and adjusting ion source parameters.Finally,by optimizing the deposition parameters,the obtained films have no film cracking effect in the outdoor environment for 20 days,and a multi-layer anti-reflection film with good anti-aging performance was obtained on the optical plastic substrate.