Patent ID: 8601835

Claim:
A method of making a lens with guaranteed optical properties, the lens having a convex lens surface and a planar lens surface, especially for a motor vehicle headlight, said method comprising the steps of: (a) providing an apparatus for making the lens, said apparatus including a lower mold part comprising a concave basin, a circumferential horizontal shoulder extending around the concave basin and a vertical peripheral rim extending vertically from the horizontal shoulder, and a horizontal facing surface on the vertical peripheral rim; an upper mold part provided with a cylindrical inner surface and comprising a mold ring, which bears with a horizontal lower surface on the horizontal facing surface of the lower mold part during precise pressing of the lens, said horizontal lower surface of the upper mold part extending inward and over the circumferential horizontal shoulder to form an intervening space adjacent to the concave basin so that said intervening space is bounded by the horizontal lower surface, the horizontal shoulder, and the vertical peripheral rim; and a press die having a planar underside and a cylindrical outer surface with a diameter; wherein said cylindrical inner surface of said upper mold part has an inside diameter that corresponds to the diameter of the press die; (b) feeding a glass melt drop into the concave basin; (c) after the feeding of step (b), precise pressing both sides of the glass melt drop in the concave basin together with the upper mold part and the press die; (d) during the precise pressing of the lens immersing the press die in the glass melt drop during the precise pressing so that a part of the glass material is displaced into the intervening space to form a supporting rim with predetermined installation dimensions on the lens, and so that the supporting rim protrudes beyond a highest point of the planar lens surface.