Method of producing optical quality glass having a selected refractive index

US6158244A · kind A · utility

Assignee

• The Regents of the University of California · US

Inventors

• John F. Poco · Livermore, US
• Lawrence W. Hrubesh · Pleasanton, US

Key dates

• Filing date: Mar 16, 1998
• Grant date: Dec 12, 2000
• Expiry date: Mar 16, 2018

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C03C2203/26
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

Optical quality glass having a selected refractive index is produced by a two stage drying process. A gel is produced using sol-gel chemistry techniques and first dried by controlled evaporation until the gel volume reaches a pre-selected value. This pre-selected volume determines the density and refractive index of the finally dried gel. The gel is refilled with solvent in a saturated vapor environment, and then dried again by supercritical extraction of the solvent to form a glass. The glass has a refractive index less than the full density of glass, and the range of achievable refractive indices depends on the composition of the glass. Glasses having different refractive indices chosen from an uninterrupted range of values can be produced from a single precursor solution.