| http://www.w3.org/ns/prov#value | - Then for the consistent production of low birefringence substrates, the chamfered substrate is etched with an etchant such as hydrofluoric acid (HF) to a depth of at least 1 ??m, preferably 1 to 3 ??m, and especially 1 to 2 ??m, prior to mirror finishing.
|
