Research On Reflective Filter Film Of Ultraviolet Detecting System

With the continuous development of optical industry,ultraviolet detection technology has gradually entered people's vision with its unique advantages,and began to develop towards an all-round,high standard direction.As an important part of the ultraviolet detection system,the filter film plays a vital role.In order to meet the needs of the ultraviolet detection system,a kind of ultraviolet filter film is studied,which can meet the technical requirements of high reflection in deep ultraviolet band and high transmission from near ultraviolet to visible band.Based on the theory of optical film design,Al₂O₃ and AlF₃ were selected as high and low refractive index materials,and the design of film system was completed on JGS1 substrate.The problem of over thickness of single film was solved by the double-sided separation method.The influence of ion assisted deposition technology on the deep ultraviolet spectrum was verified by experimental comparison,and the optical constants of materials were fitted by means of transmittance profile method.The deposition process parameters were optimized by repeated experiments.Through the comparison and analysis of the experimental results and theoretical design,the functional relationship between the film thickness and the evaporation characteristics of electron beam was established.The influence of errors on the spectra was simulated by means of the film system design software.The technical specification of the filter film was effectively improved by improving the process.Finally,the average reflectivity of the filter film is77.96%in the range of 200²70nm,and the average transmittance of the filter film is96.29%in the range of 290⁷00nm,which meets the needs of the detection system.