Patent ID: 6451719
Filing Date: 2002-09-17
Classification: C03B,C03C,G03F,Y10S

Abstract:
A silica glass optical material for transmitting light with a wavelength of from 155 to 195 nm emitted from an excimer laser or an excimer lamp, which comprises silica glass optical material of ultrahigh purity, containing from 1 to 100 wtppm of OH groups, from 5Ã—1016 to 5Ã—1019 molecules/cm3 of H2, and from 10 to 10,000 wtppm of F, but substantially free from halogens other than F, and having a fluctuation in refractive index, &Dgr;n, of from 3Ã—10âˆ’6 to 3Ã—10âˆ’7.