The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 11, 2023
Filed:
Jan. 26, 2018
Essilor International, Charenton-le-Pont, FR;
Essilor International, Charenton-le-Pont, FR;
Abstract
A method for injection molding of a weld line free minus power lens element comprises injecting a melt of thermoplastic material at a temperature higher than a glass transition temperature (Tg) of the thermoplastic material in an initial molding cavity delimited by two facing mold inserts, wherein the melt of thermoplastic material comprises at least one UV absorber. During the injecting, the two facing mold inserts are moved toward one another to define a final molding cavity whose volume is less than that of the initial molding cavity. After cooling and disassembling of the two facing mold inserts, the weld line free minus power lens element is recovered. One of the two facing mold inserts comprises a flat surface facing the initial molding cavity, thereby to form a flat surface on one side of the weld line free minus power lens element. The other of the two facing mold inserts comprises a convex surface facing the initial molding cavity, thereby to form a concave surface on an opposite side of the weld line free minus power lens element.