300mm平面标准镜装卡结构的关键参数

Key structural parameters of 300 mm aperture reference flat mirror

为了实现大口径平面标准镜的高精结构装卡,对其在重力作用下的面形变化进行了研究。首先,对结构胶的有限元建模进行了理论分析,建立了大口径平面标准镜胶结装卡结构有限元模型。然后,分析了不同胶点数量及分布、不同胶接面积以及不同镜框支撑方式等关键结构参数对参考面面形的影响。最后,设计了大口径平面标准镜胶结及支撑的结构。结果表明,采用胶点直径为5 mm,12×3胶点分布形式胶结时,参考面面形的PV值为24.06 nm,RMS值为6.78 nm,满足了大口径平面标准镜面形精度的要求。

In order to design the structures of large-aperture reference flat mirrors with high-precision,the shapes of a large-aperture reference flat mirror were studied under gravitational conditions.Firstly,the establishing method of the structure adhesive by finite element analysis was elaborated,and the finite element model of large-aperture reference flat mirror supported with adhered spots was established.Then,the influences of different number of adhered points and point distribution,different sizes of spots and support schemes on the shapes of large-aperture reference flat mirrors were researched.Finally,the structure for large-aperture flat mirror supported with adhered spots was designed.The experimental results indicate that by support scheme with 12×3 distributed and 5mm diameter adhered spots,the peak to valley（PV） value and RMS value of the reference surface is only 24.06 nm and 6.78 nm,respectively,which satisfies the requirement of shape precision of the large-aperture reference flat mirror.