环境相对湿度对光学镜面散射特性的影响

Effect of ambient humidity on scattering characteristics of optical mirror surface

在成像光学系统中,环境相对湿度会影响光学镜面污染粒子的散射特性,进而对成像光学系统性能造成影响。根据吸湿性,将污染粒子分为亲水性粒子和疏水性粒子。利用镜面污染粒子的光散射模型,分析了亲水性粒子散射效率因子随环境湿度的变化规律。在此基础上,结合亲水性和疏水性污染粒子的统计模型,分析了多粒子污染下,不同种类粒子占比和镜面洁净度等参数对光学镜面散射特性的影响。结果表明,污染粒子造成光学镜面的双向散射分布函数(BRDF)和全积分散射值(TIS)均随着环境相对湿度的增加而增大。并且,亲水性粒子比例越高,光学镜面散射损耗越强。随着光学镜面洁净度等级的减小,环境相对湿度对镜面散射损耗的影响有所减小。

In imaging optical system,the relative humidity of the environment will affect the scattering characteristics of the optical mirror surface covered with polluted particles and further affect the performance of the system.According to the hygroscopicity,the polluted particles were divided into hydrophilic particles and hydrophobic particles.By using the light scattering model of pollution particles,the variation of the scattering efficiency factor of a single hydrophilic polluted particle on the relative humidity of the environment was analyzed.On this basis,combined with the statistical models of hydrophilic and hydrophobic pollution particles,the effect of the proportion of hydrophilic particles and the cleanliness level of the mirror surface on the scattering characteristics of the optical mirror surface with multi-particles was analyzed.The results show that the bidirectional reflection distribution function(BRDF)and the total integrated scattering(TIS)caused by the polluted particles on the optical mirror surface increase with the increasing of the relative humidity of the environment.The higher the proportion of hydrophilic particles is,the stronger the scattering loss of the optical mirror surface is.As the cleanliness level of the optical mirror surface decreases,the influence of the ambient humidity on the scattering loss of the mirror surface decreases.