Current fabrication techniques for ULE® and fused silica lightweight mirrors

Fabrication of lightweight mirrors from low expansion glasses can be achieved using several techniques. Lightweighting can be obtained through fabrication of fusion-bonded cores, abrasive waterjetting (AWJ) technology and traditional fixed abrasive grinding. Lightweight cores can then be bonded to mirror plates using high temperature fusion, low temperature fusion, and frit bonding processes. Each mirror fabrication approach offers its own advantages and disadvantages in terms of lightweighting, cost and design flexibility. Each of these factors is discussed, along with Coming's proven size capability for each.