Process for the precision molding of glass articles
AssigneeCorning Glass Works
InventorsRobert J. Hagerty, Paul I. Kingsbury, Harold G. Shafer, Jr.
Life of this patent
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Abstract
Glass products such as glass lens elements are formed by an improved direct molding process at glass viscosities in the range of 10.sup.8 -10.sup.12 poises. Selected moldable alkali aluminofluorophosphate optical glasses are pressed to an optical surface finish in air utilizing an optically smooth titanium nitride molding surface, the surface being provided, for example, as a surface coating on a stainless steel mold or on a nickel chromium alloy mold supporting an electroless nickel base coating.
Claims4
In a method for molding a glass optical element having at least one curved optical surface exhibiting a precise surface figure and low light scattering, which method comprises the steps of providing a glass forming mold having a pressing surface provided with a TiN surface coating and corresponding to the optical surface, preheating the mold and a glass preform for the glass optical element to a temperature at which the glass has a viscosity in the range of 10.sup.8 -10.sup.12 poises, and pressing the mold against the preheated glass preform with pressure sufficient to conform a surface of the preform to the pressing surface of the mold, the improvement wherein:
- (a) the mold comprises a base member formed of an oxidation resistant metal;
- (b) a surface of the base member corresponding to the pressing surface of the mold is provided with a machinable nickel base coating;
- (c) the nickel base coating is provided with a TiN glass contact coating;
- (d) the glass preform consists of an alkali fluoroaluminophosphate glass;
- and
- (e) the step of pressing the mold against the preheated glass preform is carried out in air.
Dependencies are inferred from the claim text.