| At present,a new type of"self-focusing laser pyrotechnic system technology"has received extensive attention on researchers.This new type of pyrotechnic technology,due to its advantages such as miniaturization,greater safety and reliability and so on is widely used by researchers in weapon systems to achieve miniaturization of detonation systems,improve the safety and reliability of missiles and warhead charge,and thus enhance their destructive effectiveness.The safety and reliability of self-focusing laser pyrotechnic system technology is realized by plating optical thin film on the surface of the lens in the pyrotechnic,combined with the self-focusing pyrogenic self-diagnosis system.However,in the sealed packaging of the fire product,when the package of the fire product is packaged by high temperature welding,the high temperature in the welding process will influence the stability of the film performance on the surface of the lens,and then affect the stability of 980nm ignition and 1310nm self-test band laser transmission in the fire product.Therefore,it is important to design and prepare a laser film with spectral performance,thermal stability,and good surface quality under thermal shock.In this project,the author will carry out specific experimental research in the following three parts.1)Through the Comsol multiphysics simulation software,the temperature field and stress field are combined to establish a 3D model of self-focusing laser pyrotechnics carry out the simulation analysis of different welding and sealing processes.Among them,the temperature is pre-heated to 380℃for heat preservation treatment for a period of time,and then the temperature is raised to 430℃for welding treatment,and after 20min of treatment,it is cooled with the furnace.The release of stress and strain on the surface of the lens will be the most gentle and will not cause too much impact on the surface film.In this process,the film on the surface of the lens is annealed at approximately 400℃.2)Combined with the simulation results of Comsol,two thermal shock treatment studies were determined.For the selected Ti O2and Si O2film materials,two thermal shock treatment studies of the film were carried out on the quartz substrate.It is concluded that thermal shock treatment at an appropriate temperature in advance can ensure the optical properties and thermal stability of the film under high temperature impact.3)According to the requirements of performance indicators,the laser film structure of cut-off filter,substrate and anti-reflection film is proposed.With quartz as the base,TFCalc and electron beam thermal evaporation technology were used to plate a laser film with qualified spectral indicators.The high temperature thermal shock study of 400℃was carried out on the coated laser film and two heat shock treatment studies.It is concluded that the quality of the laser thin film surface is good under the high temperature thermal shock of 400℃,and the changes of the spectral peaks in the 980nm and 1310nm bands also meet the expected requirements.In the two thermal shock treatment experiments,it was found that thermal shock treatment with appropriate temperature in advance was helpful to improve the phenomenon of blue shift and peak drop of laser film spectral curve under high temperature thermal shock.A self-focusing lens ofΦ1.8mm was found for the preparation of laser thin film samples.Based on the light intensity method,a spectral detection device was built,and the transmittance of the laser film at 980nm was 98.09%and the reflectivity of 1310nm was 98.02%.The prepared laser film was subjected to high temperature thermal shock treatment at 400℃,and the measured 980nm transmittance and1310nm reflectance changes did not exceed 2%,which met the requirements of the index,and the surface quality of the treated film was good. |
