大口径精密光学元件低应力支撑结构研究

为了实现倾斜安装放置状态的大口径精密光学元件低应力支撑结构分析设计,采用有限元分析方法,对45°倾斜角安装放置的精密光学透镜在自重作用下的镜面面形进行了研究。首先,建立了光学透镜不同胶结结构的有限元模型,从镜面对角线横截面自重变形及镜面面形的波面误差两方面,分析了两种胶结分布方式及不同胶点大小对镜面面形的影响。然后,在胶结结构基础上,建立了不同镜框支撑结构有限元模型,从镜面面形的波面误差方面,分析了支撑力分布方式对镜面面形的影响。最后,设计了胶结及镜框支撑的低应力支撑结构。分析结果表明,采用胶点直径为30 mm,矩形分布形式胶结,侧面均匀方式支撑镜框时,镜面面形的波面误差PV值为16.608 nm,RMS值为7.9385 nm,满足瑞利判据的要求,验证了支撑结构的合理性。

Study on low-stress supporting structure for large-aperture precision optical element

In order to analysis and design the low-stress supporting structure for the slant setting large-aperture precision optical element,the mirror figure of a slant setting optical transmitting mirror with a tilt angle of 45° under gravity load is studied by using finite element analysis method.Firstly,the finite element models of the optical transmitting mirror with different cemented structures are established,and the influences of the two cementation distribution ways and the different sizes of the glue dots on the mirror figure are analyzed from two aspects of cross-section self-weight deformation of the mirror diagonal and the wave surface error of the mirror figure.Then based on the cemented structures,the finite element models of different lens frame supporting structures are established,and the influence of supporting force distribution way on the mirror figure is analyzed from the aspect of the wave surface error of the mirror figure.Finally,the low-stress supporting structure for cementing and lens frame supporting is designed.The analysis results show that when the diameter of the glue dot is 30 mm,cementing by the way of rectangular distribution and supporting the lens frame by the way of side uniform support,the PV value and RMS value of the wave surface error of the mirror figure are 16.608 nm and 7.93895 nm respectively,which meet the requirements of the Rayleigh criterion and verify the reasonableness of the support structure.