Method of producing moulds for organic polymer multifocal lenses
AssigneeCorning Incorporated
InventorMilford L. Buckley
Life of this patent
Estimating the term…
Abstract
A method is disclosed for constructing a glass mould, and particularly the primary glass mould member, for use in casting multifocal, ophthalmic lenses from organic polymers. The method comprises pressing a glass segment with a cavity, removing the base portion of the segment to form a perforation, mounting the perforated segment on a second glass body, and fusing the assembly to form a blank for finishing. For trifocal lenses, a composite, perforated segment is formed and sealed in a depression on a major element to form a blank.
Claims4
In an improved method of forming a contoured surface on a primary glass mould member, said mould member being adapted to mould a reverse contoured surface on an organic polymer multifocal ophthalmic lens, each contoured surface comprising two surfaces of curvature, each having a different radius of curvature and the edge of one surface of curvature being spaced from the other by a wall, the spacing wall between the two surfaces of curvature being at an angle of 10-15 degrees to a plane normal to the second surface to permit opening of the glass mould member to remove a moulded organic lens without damage to the lens, the improvement comprising pressing a glass segment with a cavity having a base forming a web and a portion of its vertical wall slanting outwardly at an angle of 10-15 degrees to a vertical plane, removing the web to form a perforated segment having a predetermined convex curvature corresponding to the concave curvature of a body to which the perforated segment is to be fusion sealed, placing the perforated segment on the body, fusion sealing the two bodies together to form a fused assembly, and then grinding the fused assembly to a desired major curvature whereby a portion of the slanted portion of the perforated segment wall remains as the separating wall between two surfaces of curvature on the contoured surface of he primary mould member, thereby permitting the glass mould to be opened to remove a moulded organic lens without damage to the lens.
A method of forming a primary, glass mould member to produce an organic polymer, trifocal lens which comprises pressing two glass segments, each with an open cavity extending upwardly from a web across the bottom of the segment, one of said cavities being larger than the other and each having a portion of its cavity wall slanting outwardly at an angle of 10-15 degrees with the vertical plane, removing the web from one cavity segment in such manner as to provide a perforated segment, the bottom of such segment having a predetermined convex surface of curvature, imparting a concave surface of curvature to the top surface of the segment with the smaller cavity that corresponds to the convex surface of curvature on the segment with the larger cavity, resting the larger perforation segment atop the smaller cavity segment with the slanting wall portions of each coinciding, fusing the two segments to form an integral segment, removing the base of the integral segment to produce a perforated composite having a convex surface of curvature, placing the composite in a depression on the face of a major element in a position displaced from the center line of the major, the slanted portion of the composite wall being oriented inwardly toward the center line, fusing the composite segment in the depression and imparting a desired surface of curvature to the upper surface of the fused body.
Dependencies are inferred from the claim text.