The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 16, 1997
Filed:
Sep. 11, 1996
John E Maxon, Canton, NY (US);
Corning Incorporated, Corning, NY (US);
Abstract
Fused silica boules (19) having improved homogeneity are produced by causing the boule (19) to flow radially during its formation to achieve local mixing between portions of the boule which may have experienced different laydown conditions. The mixing is achieved by one or a combination of: (1) use of a containment vessel (13) having a gently sloping containment wall (22); (2) use of a containment vessel (13) whose inner radius (r.sub.v) is substantially larger than the outermost radius (r.sub.b) of the burners (14) used to produce the boule (19); and/or (3) maintaining the boule (19) at a sufficiently high temperature during laydown so that radial flow is achieved with a minimum head height of glass. Large blanks having high homogeneity can be made from such boules, e.g., blanks having diameters above 200 millimeters and .DELTA.n values of less than 0.25.times.10.sup.-6.