Suppressing the edge roll off in continuous polishing of large planar optics by using extension blocks

The edge roll off seriously restricts the further improvement of the overall surface figure accuracy in CP of large planar optics. Firstly, the half width and depth of large planar optics’ edge region is proposed to quantify the roll off degree by analyzing its radial equivalent profile. Then, a two-dimensional symmetrical model of the large planar optics and the pitch lap is established. Next, based on the finite element model, the influence of extension block’s bonding state on the large planar optics edge’s stress concentration is analyzed. Finally, the effectiveness of this proposed method is verified by CP of large planar optics with extension blocks.