METHOD FOR LOADING A BLANK COMPOSED OF FUSED SILICA WITH HYDROGEN, LENS ELEMENT AND PROJECTION LENS

摘要

A method for loading a blank composed of fused silica with hydrogen, including loading the blank at a first temperature (T₁) and a first hydrogen partial pressure (p₁), and further loading the blank at a second temperature (T₂) which is different from the first temperature and at a second hydrogen partial pressure (p₂) which is different from the first hydrogen partial pressure. The first and second temperatures (T₁, T₂) are lower than a limit temperature (T_L) at which a thermal formation of silane in the fused silica of the blank commences. Also disclosed are a lens element produced from such a blank and a projection lens that includes at least one such lens element.