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:
Jul. 25, 1989
Filed:
Jan. 26, 1988
Hiroyuki Sakai, Fussa, JP;
Shigeaki Ohmi, Tokorozawa, JP;
Yoshitaka Yoneda, Akishima, JP;
Yoshiyuki Asahara, Mizuho, JP;
Hoya Corporation, Tokyo, JP;
Abstract
A uniform refractive index-type glass is prepared by ion exchange in which a glass containing ions of a first type is immersed in a molten salt containing ions of a second type, the ions in the molten salt having a higher refractive index than the ions in the glass. The glass is removed from the molten salt at a predetermined point and before the saturation point or equilibrium and the ion distribution becomes uniform throughout the glass. The concentration of first and second ions is not uniform from the center of the glass to its outer surface. The glass is next heated to make the concentrations of the first and second ions substantially uniform throughout the glass from the center to the outer surface. Optionally, this glass is then immersed in a molten salt containing a third type of ion having a lower refractive index than the second ion for exchange with part of the ions in the second type. A gradient refractive index-type glass in which the concentration of the second type of ions decreases parabolically from the center of the glass to the outer surface while the concentration of the third type of ions increases parabolically from the center of the glass to the outer surface.