Patent ID: 7981824
Filing Date: 2011-07-19
Classification: C03B,C03C

Abstract:
1. A quartz glass blank for an optical component for transmitting radiation of a wavelength of 15 nm and shorter, said blank being cylindrical and having a cylinder axis with a height, and comprising highly pure quartz glass, doped with titanium and/or fluorine, wherein said quartz glass has: a) micro-inhomogeneities caused by a local variance of a distribution of TiO b) a thermal expansion coefficient, averaged over the height of the cylinder axis, varying over an optically used surface of the quartz glass blank with a maximum inhomogeneity of less than 5 ppb/K; c) the thermal expansion coefficient varying along the optically used surface substantially according to Δα from the formula (1): wherein a residual inhomogeneity of the thermal expansion coefficient after subtraction of Δα according to the formula (1) from the thermal expansion coefficient is not more than 0.5 ppb/K, where C 0 α <5 ppb/K; d) the thermal expansion coefficient having a radial variance over the optically used surface of the quartz glass blank of not more than 0.4 ppb/(K cm); and e) a stress birefringence at 633 nm averaged over the height of the cylinder axis of not greater than 2 nm/cm and not greater than a maximum stress birefringence (SDB) that varies over the optically used surface of the quartz glass blank substantially according to the formula (2): where r is a radial distance from the cylinder axis; R is a maximum radius of the optically used surface; and C