Patent ID: 7232778
Filing Date: 2007-06-19
Classification: C03B,C03C

Abstract:
1. A synthetic quartz glass ingot, which is produced by vapor phase hydrolyzing or oxidatively decomposing a silica-forming starting compound in an oxyhydrogen flame such that silica growth in a direction occurs at a silica particle deposition and melting face, and which has striae, wherein the striae visible when viewed in a direction perpendicular to the silica growth direction are distributed periodically in the silica growth direction, the striae have a distribution of at least one stria per centimeter in the silica growth direction, the striae have a shape which is axially symmetric about the center axis of the growth face and arches out toward the periphery, and the striae have a visibility which meets striae grade B, grade C or grade D of U.S. military specification MIL-G-174B.