Method of manufacturing biconvex lens elements and element formed thereby

Abstract

A method of manufacturing biconvex lens elements (21) comprising a biconvex glass lens (23) and a holder (1) consisting of two cylindrical rings (5,7), which are telescopically slidable with respect to each other and have different diameters so that an annular gap (9) is formed. A lens blank is heated together with the holder (1) in the telescopically extended position of the rings (5,7) to the processing temperature of the glass and is arranged between the heated dies (17, 19) of a mould, whereupon the dies (17, 19) are moved towards each other in a pressing stroke, the two rings (5,7) being telescoped into each other, the lens blank in the holder being moulded into a biconvex glass lens (23) and the excess quantity of glass being pressed from the hotter central part of the lens blank into the annular gap (9). The lens element (21) obtained after cooling is characterized by a biconvex glass lens (23), which is FIG. 7.

Dependencies are inferred from the claim text.