Patent ID: 6143676
Filing Date: 2000-11-07
Classification: C03B,C03C

Abstract:
A synthetic silica glass optical material for use with ultraviolet rays in the wavelength region from 165 to 195 nm, made from ultra-high purity synthetic silica glass, containing OH groups at a concentration of from 5 to 300 wtppm with a fluctuation in OH-group concentration (.DELTA.OH/cm) equal to or less than 10 wtppm, containing hydrogen molecules at a concentration of from 1.times.10.sup.17 to 1.times.10.sup.19 molecule/cm.sup.3 with a fluctuation in hydrogen molecule concentration (.DELTA.H.sub.2 /cm) equal to or less than 1.times.10.sup.17 molecule/cm.sup.3, and containing chlorine at a concentration equal to or less than 50 wtppm.