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:
Mar. 03, 1992
Filed:
Jan. 25, 1991
Glaverbel, Brussels, BE;
Abstract
Dealkalized sheet glass having a core region which is not dealkalized, having a pre-dealkalization bulk sodium ion concentration of at least 8%, calculated as weight percent sodium oxide in the sheet glass, which pre-dealkalization bulk sodium ion concentration continues to be maintained in the core region of the sheet glass, and having a surface which is dealkalized to a depth such that a sodium ion concentration gradient exists. The sodium ion depletion is maximum at the surface, the depth at which the sodium ion concentration is 90% of the pre-dealkalization bulk sodioum ion concentration is at least twice the depth at which the sodium ion concentration is 50% of the predealkalization bulk sodium ion concentration, and the sodium ion concentration at a depth of 50 nm is not more than 50% of the pre-dealkalization bulk sodium ion concentration. A long-lasting dealkalization is achieved because of a reduced tendancy to ionic migration due to the shape of said sodium ion concentration gradient.